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Indian Standard Time

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For Irish Standard Time, seeTime in the Republic of Ireland.

Indian Standard Time
Time zone
UTC offset
ISTUTC+05:30
Current time
13:33, 30 August 2024IST[refresh]
Observance ofDST
DST is not observed in this time zone.

Indian Standard Time(IST), sometimes also calledIndia Standard Time,is thetime zoneobserved throughout theRepublic of India,with atime offsetofUTC+05:30.India does not observedaylight saving timeor other seasonal adjustments. Inmilitary and aviation time,IST is designatedE*( "Echo-Star" ).[1]It is indicated asAsia/Kolkatain theIANA time zone database.

History

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Main article:Time in India

The Indian Standard Time was adopted on 1 January 1906 during theBritish erawith the phasing out of its precursorMadras Time(Railway Time),[2]and afterIndependence in 1947,theUnion governmentestablished IST as the official time for the whole country, althoughKolkataandMumbairetained their own local time (known asCalcutta TimeandBombay Time) until 1948 and 1955, respectively.[3]The Central observatory was moved fromMadrasto a location at Shankargarh Fort inAllahabad district,so that it would be as close toUTC+05:30as possible.[4]

Daylight Saving Time (DST) was used briefly during theChina–India War of 1962and the Indo-PakistaniWars of 1965and1971.[5]

Former timezones

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Time Zone UTC Period Purpose
Bombay Time UTC+04:51 1884–1955 Official
Calcutta Time UTC+05:53:20 1884–1948 Official
Madras Time UTC+05:21:14 1802–1906 Railways
Port Blair mean time UTC+06:10:37 19th century–1906 Local

Calculation

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Location of Mirzapur (near Allahabad) and the 82°30’ E longitude that is used as the reference longitude for IST

Indian Standard Time is calculated from the reference longitude of IST at 82°30'E passing near Mirzapur.[6]In 1905, the meridian passing east of Allahabad was declared as a standard time zone forBritish Indiaand was declared as IST in 1947 for theDominion of India.[7]This longitude of 82°30'E was chosen as thestandard meridianfor the whole country[8]as it is located centrally betweenwestern India(local time UTC +05:00) andnortheastern India(local time UTC +06:00). Currently, theCouncil of Scientific and Industrial Research- National Physical Laboratory(CSIR-NPL) maintains the Indian Standard Time with the help of theAllahabad Observatory.[9]

Criticism and proposals

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The country's east–west distance of more than 2,933 kilometres (1,822 mi) covers over 29° of longitude, resulting in the sun rising and setting almost two hours earlier on India'seasternborder than in theRann of Kutchin the far west. Inhabitants of thenortheastern stateshave to advance their clocks with the early sunrise to avoid the extra consumption of energy after daylight hours.[6]

In the late 1980s, a team of researchers proposed separating the country into two or three time zones to conserve energy. The binary system that they suggested involved a return to British-era time zones, but the recommendations were not adopted.[6][10]

In 2001, the government established a four-member committee under theMinistry of Science and Technologyto examine the need for multiple time zones and daylight saving.[6]The findings of the committee, which were presented toParliamentin 2004 by the Minister of Science and Technology,Kapil Sibal,did not recommend changes to the unified system, stating that 'the prime meridian was chosen with reference to a central station, and that the expanse of the Indian State was not large.'[11]

Though the government has consistently refused to split the country into multiple time zones, provisions in labour laws such as thePlantations Labour Act, 1951allow the union and state governments to define and set the local time for a particular industrial area.[12]InAssam,tea gardens follow a separate time zone, known as theChaibaganorBagantime ('Tea Garden Time'), which is one hour ahead of IST.[13]Still, Indian Standard Time remains the only officially used time.

In 2014, Chief Minister of AssamTarun Gogoistarted campaigning for another time zone forAssamand othernortheastern statesof India.[14][15]However, the proposal would need to be cleared by theunion government.

In June 2017, theDepartment of Science and Technology(DST) indicated that it is once again studying the feasibility of two time zones for India. Proposals for creating an additional Eastern India Time (EIT atUTC+06:00), shifting default IST toUTC+05:00and daylight saving (Indian Daylight Time for IST and Eastern India Daylight Time for EIT) starting on 14 April (Ambedkar Jayanti) and ending on 2 October (Gandhi Jayanti) was submitted to DST for consideration.[16][needs update]

Time signals

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Official time signals are generated by theTime and Frequency Standards Laboratoryat the National Physical Laboratory inNew Delhi,for both commercial and official use. The signals are based onatomic clocksand synchronised with the worldwide system of clocks that supportCoordinated Universal Time.

Features of the Time and Frequency Standards Laboratory include:

  • High-frequencybroadcast service operating at 10 MHz under call signATAto synchronise the user clock within a millisecond;
  • Indian National Satellite Systemsatellite-based standard time and frequency broadcast service, which offers IST correct to ±10 microsecond and frequency calibration of up to ±10−10.
  • Time and frequency calibrations made with the help ofpico-andnanosecondstime intervalfrequency countersandphaserecorders.

IST is taken as the standard time as it passes through almost the centre of India. To communicate the exact time to the people, the exact time is broadcast over the nationalAll India RadioandDoordarshantelevision network. Telephone companies have dedicated phone numbers connected to mirrortime serversthat also relay the precise time. Another increasingly popular means of obtaining the time is throughGlobal Positioning System(GPS) receivers.[17]

See also

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References

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  1. ^"Military and Civilian Time Designations".Greenwich Mean Time.Retrieved2 December2006.
  2. ^Menon, Nitya (22 August 2014)."When Madras clocked the time".The Hindu.Retrieved1 January2023.
  3. ^"Odds and Ends".Indian Railways Fan Club.Retrieved25 November2006.
  4. ^"India Standard Time".The Hans India.Hyderabad Media House Limited. 19 April 2018.Retrieved27 June2021.
  5. ^"India Time Zones".Greenwich Mean Time.Archived fromthe originalon 19 May 2007.Retrieved25 November2006.
  6. ^abcdSen, Ayanjit (21 August 2001)."India investigates different time zones".BBC News.Retrieved25 November2006.
  7. ^"September 1, 1947: How Indian Standard Time was introduced in country".timesnownews.Retrieved19 April2022.
  8. ^"Indian Standard Time: Lack of Scientific Temper".The Times of IndiaBlog.10 June 2021.Retrieved19 April2022.
  9. ^"How Indian Standard Time was introduced in India on September 1, 1947 - Explained".Jagranjosh.1 September 2021.Retrieved19 April2022.
  10. ^Muthiah, S. (24 September 2012)."A matter of time".The Hindu.Archived fromthe originalon 24 March 2002.Retrieved25 November2006.
  11. ^"Standard Time for Different Regions".Department of Science and Technology.22 July 2004. Archived fromthe originalon 28 September 2007.Retrieved25 November2006.
  12. ^"A matter of time".National Resource Centre for Women.Archived fromthe originalon 19 March 2006.Retrieved25 November2006.
  13. ^Rahul Karmakar (24 September 2012)."Change clock to bagantime".Hindustan Times.Archived fromthe originalon 6 June 2011.Retrieved22 September2008.
  14. ^"Gogoi for separate time zone for Assam - Times of India".The Times of India.Retrieved10 May2018.
  15. ^"India could get second time zone with Assam one hour ahead".ndtv.
  16. ^"Government assessing feasibility of different time zones in India".The Economic Times.22 June 2017.Retrieved18 August2017.
  17. ^"Satellites for Navigation".Press Information Bureau, Government of India.Retrieved25 November2006.
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